The present invention relates to a steering wheel with an external shell made of composite materials and the method of manufacturing the same.
Steering wheels for automobiles are presently made of an internal metallic core covered by resin and of an external coating and finishing shell, made of various materials, which represents the appearing part of the steering wheel.
Among the several known processes for manufacturing steering wheels is the process comprising providing for formation of two half-shells by hot pressing of one or more material sheets inside molds of suitable shape, subsequent mechanical flattening working of the junction line of the two half-shells, application of the half-shells on a steering wheel body formed by a metallic core covered by resin and mutual fixing of the two half-shells along said junction line.
An object of the present invention is to improve this known process to make it particularly suitable for providing a steering wheel with half-shells of composite materials solidly joined together.
According to the invention, this object is obtained by a process comprising preparation of piles of sheets of composite materials, hot molding thereof for obtaining respective half-shells with a shape corresponding to that of respective halves of the steering wheel being manufactured, mechanical flattening of the front surfaces of the two half-shells, application of the two half-shells to opposite parts of a steering wheel body formed by a metallic core covered by resin and mutual fixing of the two half-shells along said front surfaces, characterized in that after flattening said front surfaces of the two half-shells are mechanically worked to form respective complementary teeth which can be male-female coupled when the two half-shells are applied around said steering wheel body.
It has been possible to verify that the presence of complementary teeth at the junction lines of the two half-shells allows to provide a very strong connection between the half-shells which is able to resist all the aging and safety test required by the automobile manufacturers.